Patent GB-788842-A (GB)
Title: Improvements in or relating to organopoly-siloxanes
IPC: C08G77/00
Filed: 1956-05-23
Abstract: Organopolysiloxanes, useful as adhesives, lubricants, emulsifying agents, sizing for glass fibres and as intermediates in the preparation of silicone-alkyd resins, have the unit general formula: <FORM:0788842/IV (a)/1> wherein Y is a methyl radical or hydrogen atom, R is an alkyl radical or a hydrogen atom and R1 is a monovalent hydrocarbon radical free from aliphatic unsaturation.  The compounds in which Y is hydrogen are best made by reacting a silane of the formula: <FORM:0788842/IV (a)/2> with the sodium derivative of malonic ester in accordance with the process of Specification 685,553, [Group XXVIII], and saponifying and decarboxylating the resulting dialkoxy malonate derivative by heating with glacial acetic acid and hydrochloric acid, simultaneous hydrolysis of the alkoxy radicals occurring to yield a polysiloxane acid.  Conversion of these acids to acyl chlorides is effected by treatment with thionyl chloride or phosphorus chlorides and reaction with an alcohol gives the corresponding carboxylic acid esters.  The compounds where Y is methyl are best made by reacting the corresponding methacrylate esters with a silane of the formula R1SiHCl2 in the presence of platinum dispersed on finely divided charcoal at room temperature or by heating to below 150 DEG  C. and hydrolysing the resulting chlorosilanes; the ester groups may then be hydrolysed to the corresponding acids by heating with aqueous acid or alkali.  The novel compounds may be co-polymerized with conventional siloxanes of the general formula: <FORM:0788842/IV (a)/3> where R11 is an alkyl, alkenyl, cycloaliphatic, aralkyl or aromatic radical and n has a value from 1 to 3, in amounts to yield copolymers composed of from 0.1 to 99.9 mol. per cent of the novel siloxane units and from 99.9 to 0.1 mol. per cent of the conventional siloxane units.  The copolymers may be made in known manner (1) by interacting the respective siloxanes in the presence of sulphuric or hydrochloric acid, or (2) by co-hydrolysing the corresponding chlorosilanes.  The copolymers are useful as lubricants, coating compositions and as raw materials in making siloxane rubber.  In examples the following polymers, in which "Me,", "Bu", "Vi", "Et" and "Ph" represent respectively methyl, butyl, vinyl, ethyl and phenyl radicals, were made by the above described methods; <FORM:0788842/IV (a)/4> from chloromethylmethyldichlorosilane and diethyl malonate; <FORM:0788842/IV (a)/5> from the siloxane acid of (1) and ethanol; <FORM:0788842/IV (a)/6> and <FORM:0788842/IV (a)/7> from the ester of (2) and hexamethyldisiloxane; <FORM:0788842/IV (a)/8> wherein x has an average value of less than 10, from the acid of (1) and hexamethyldisiloxane; (5) copolymers of Me2SiO and <FORM:0788842/IV (a)/9> units from the acid of (1) and octamethylcyclotetrasiloxane; <FORM:0788842/IV (a)/100> and diethyl malonate and the copolymers therefrom containing ViSiO 3/2 , Ph.MeSiO, Ph2SiO, Me2SiO and <FORM:0788842/IV (a)/111> from n.butyl methacrylate and methyldichlorosilane, and the siloxane ester <FORM:0788842/IV (a)/122> and acid <FORM:0788842/IV (a)/133> therefrom; <FORM:0788842/IV (a)/144> from methylmethacrylate and methyl dichlorosilane, and the siloxane ester <FORM:0788842/IV (a)/155> therefrom; <FORM:0788842/IV (a)/166> from phenyl dichlorosilane and methyl methacrylate and the siloxane ester <FORM:0788842/IV (a)/177> and acid <FORM:0788842/IV (a)/188> therefrom; Ph.Me.SiO and Ph.SiO 3/2 units from the corresponding silanes; (1/) a copolymer similar to (10) except that <FORM:0788842/IV (a)/199> is replaced by <FORM:0788842/IV (a)/200> from <FORM:0788842/IV (a)/211> and Me3.SiCl.  The copolymers of (10) and (11) may be reacted with polyhydric alcohols and polybasic acids to form silicone-alkyd resins.